The present disclosure relates to a battery device comprising a battery.
Japanese Patent No. 5592194 discloses a battery device that comprises a battery and a cell voltage monitoring circuit; the battery comprises a plurality of serially-coupled cells, and the cell voltage monitoring circuit monitors respective cell voltages of the plurality of cells.
It has been known that the cell voltage monitoring circuit has a cell overdischarge detection function for detecting overdischarge of any of the cells. In the cell overdischarge detection function, the cell voltage monitoring circuit carries out a specified process (for example, outputs a specified signal) when any of the cells is in an overdischarge state. The cell voltage monitoring circuit is generally configured to operate with an electric power supplied from the battery.
In the above-described battery device, if the electric power is continuously supplied to the cell voltage monitoring circuit from the battery even after any of the cells has become overdischarged, such an overdischarge state of the overdischarged cell further proceeds, causing failure of this cell; consequently, the battery may not be used anymore. In a case of an inexpensive battery device having a relatively small charge capacity, it is highly likely that if a cell enters the overdischarge state, the overdischarge state quickly proceeds, resulting in failure of the overdischarged cell.
In this regard, there is a known technique to interrupt the supply of the electric power to the cell voltage monitoring circuit from the battery when the cell voltage monitoring circuit detects the overdischarge state of any of the cells. With this technique, when any of the cells enters the overdischarge state, the supply of the electric power to the cell voltage monitoring circuit from the battery is interrupted, thereby stopping an operation of the cell voltage monitoring circuit. Consequently, it is possible to inhibit development of the overdischarge state of the cell.